Colo. Rev. Stat. § 3-1-110
Whenever any officer or officers of the United States thereunto duly authorized, shall designate or select a tract of sufficient area within the corporate limits of the city of Leadville as and for the site of a public building, and the title thereto shall have been conveyed and confirmed to the United States of America by the owner or owners thereof, the governor of this state shall make, execute, and deliver to the United States of America a deed, sealed with the great seal of the state of Colorado and attested by the secretary of state, containing apt, meet, and proper words, clauses, and covenants to fully cede, give, grant, transfer, confer, and confirm exclusive jurisdiction for all purposes whatsoever over such tract of land, and all and every part thereof, unto the United States of America; but, nevertheless, therein reserving to this state, jurisdiction to serve the civil process of state, county, and municipal courts and tribunals within said tract of land, to serve and execute therein processes in criminal cases by state, county, and municipal officers in respect to offenses, misdemeanors, crimes, and felonious acts committed outside of said tract, and at, from, and after the making, executing, ensealing, attesting, and delivery of such deed, exclusive jurisdiction shall vest in and remain in the United States of America for and during all the time the United States shall remain the owner of said tract, subject only to the state jurisdiction for the service of execution and process reserved to this state over said tract of land so ceded, granted, transferred, confirmed, and conferred unto the United States of America for and during the time the United States shall remain the owner thereof.
C.R.S. § 3-1-110